California Water Issues AGST 3000 Agriculture, Society and the Natural World Whiskeys for drinkin and waters for fighting for…. Mark Twain.

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Presentation on theme: "California Water Issues AGST 3000 Agriculture, Society and the Natural World Whiskeys for drinkin and waters for fighting for…. Mark Twain."— Presentation transcript:

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California Water Issues AGST 3000 Agriculture, Society and the Natural World Whiskeys for drinkin and waters for fighting for…. Mark Twain

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Californias Major Water Users: Agriculture – irrigated farm land, a huge economic engine for the state. Environment – fish and other wild life have specific water requirements. Families – human factor, showers, dishes, swimming pools and golf courses. Manufacturing – processing, cooling produce jobs for the state which generate a tax base.

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Water Terminology Acre-foot An acre-foot equals the amount of water needed to cover an acre of land to the depth of one foot (326,000 gallons) and is approximately the amount of water used by an average family of four during one year. Overdraft The deficit between pumped water from a groundwater basin and the long-term recharge.

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Californias Tug of Water Water Use Tugs Water Use Tug #1: 80% of water demand occurs south of Sacramento North versus South Water Use Tug #2: There is also an East versus West use conflict Water Use Tug #3: Water demand is highest in the summer when availability is lowest Water Use Tug #4: Environmental water use conflicts with agriculture, urban need. Water Use Tug #5: Agriculture versus Urban use: who gets how much and when, etc.? Water Use Tug #6: What are the water rights for various interest groups in the future?

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Figure 1. Freshwater Consumption as a Percentage of Local Average Annual Precipitation. (Source: USDA-NRCS, 2001)

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Californias Water Supply Californias ground water Californias groundwater basins store about 850 million acre-feet of water. (Less than 50% is unavailable for use due to depth of water table.) Californias groundwater basins store about 850 million acre-feet of water. (Less than 50% is unavailable for use due to depth of water table.) For long term sustainability, groundwater cannot be removed that will not be replenished. For long term sustainability, groundwater cannot be removed that will not be replenished. 15 million acre-feet of groundwater is pumped each year. 15 million acre-feet of groundwater is pumped each year. 20% of the states water requirements are met with pumped groundwater. 20% of the states water requirements are met with pumped groundwater. CA is operating on a 1.3 million acre-foot overdraft. CA is operating on a 1.3 million acre-foot overdraft. CA groundwater is recharged by: CA groundwater is recharged by: 1) Nature – rain & snow (7 million acre-foot annually) 1) Nature – rain & snow (7 million acre-foot annually) 2) After usage – agriculture & industry (6.65 million acre-feet /yr.) 2) After usage – agriculture & industry (6.65 million acre-feet /yr.) 3) Recharge programs – Los Angeles municipal water 3) Recharge programs – Los Angeles municipal water

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Californias surface water Comes from an average annual statewide precipitation of almost 24 inches. (Ranging from almost nothing in the deserts to more than 100 inches in the northern mountains) Comes from an average annual statewide precipitation of almost 24 inches. (Ranging from almost nothing in the deserts to more than 100 inches in the northern mountains) Sixty percent of the precipitation is evaporated or transpired by trees and vegetation. Sixty percent of the precipitation is evaporated or transpired by trees and vegetation. The remaining forty percent equals about 71 million acre-feet of stream flow (in an average rainfall year). The remaining forty percent equals about 71 million acre-feet of stream flow (in an average rainfall year). Colorado River flows diverted to California supply 4.8 million acre-feet. Colorado River flows diverted to California supply 4.8 million acre-feet.

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Californias surface water continued… Inflow streams from Oregon add an addition 1.4 million acre-feet. Inflow streams from Oregon add an addition 1.4 million acre-feet. This means in an average year California has available slightly more than 78 million acre-feet of water. This means in an average year California has available slightly more than 78 million acre-feet of water. However, not all of this water can be collected for use (almost 29 million acre-feet occurs in the north coast region alone and much of it is unavailable for use). However, not all of this water can be collected for use (almost 29 million acre-feet occurs in the north coast region alone and much of it is unavailable for use).

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Agricultures Water Use: 80% of developed supply (reservoir storage, irrigation districts, state and federal water projects) 80% of developed supply (reservoir storage, irrigation districts, state and federal water projects) 28-35 million acre-feet depending on yearly rainfall 28-35 million acre-feet depending on yearly rainfall Irrigated acres 2002-8,709,3531997-8,886,693 Irrigated acres 2002-8,709,3531997-8,886,693 Irrigated acreage is declining due to urban growth and water cut backs by federal/state projects. Irrigated acreage is declining due to urban growth and water cut backs by federal/state projects. A large percentage of agriculture water percolates back into ground or streams (around 5 million acre-feet contributes to re-charge) A large percentage of agriculture water percolates back into ground or streams (around 5 million acre-feet contributes to re-charge)

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Urban and Environmental Water Use CA urban use is about 7.8 million acre-feet. CA urban use is about 7.8 million acre-feet. One acre of houses uses approximately the same amount of water as an acre of agriculture crops (what happens to this water?) One acre of houses uses approximately the same amount of water as an acre of agriculture crops (what happens to this water?) 26 million acre-feet is diverted to environmental uses during normal years less in drought years) 26 million acre-feet is diverted to environmental uses during normal years less in drought years) 9.56 million acre-feet for the Delta 9.56 million acre-feet for the Delta 17.8 for wild and scenic river flows 17.8 for wild and scenic river flows This amount is expected to increase This amount is expected to increase

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Regional Water Use Central Valley 19 million acre-feet Central Valley 19 million acre-feet Sacramento River 11.7 million acre-feet Sacramento River 11.7 million acre-feet South Coast 4.6 million acre-feet South Coast 4.6 million acre-feet Colorado River 4 million acre-feet Colorado River 4 million acre-feet

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Groundwater supply initially huge Maybe as much as 750,000,000 acre feet accumulated over thousands of years Efficient pumps developed around 1920 Irrigated acreage rapidly expanded several fold Groundwater levels began to drop precipitously subsidence ground is actually sinking.

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IRRIGATION A. Definition: Supplying water to plants in an artificial manner. (39% of all freshwater in the US is used to irrigate crops) 1. Ancient practice – first irrigation used ditches to divert rivers and streams. 2. California agriculture relies on irrigation. a. Mediterranean climate b. Crop diversification c. Economics

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Population Water Needs According to U.S. Census Bureau figures, Californias population currently is 35.1 million, and is projected to hit 49.3 million by 2025. 1998 California Water Plan update: the state Department of Water Resources (DWR) forecast a gap between water supply and demand ranging from 2.4 million acre-feet during normal years up to 6.2 million acre-feet in drought years by 2020. The next water plan is due in 2003

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An acre-foot = An acre-foot of water is about 326,000 gallons – enough to cover an acre of land, about the size of a football field, 1 foot deep and meet the average needs of between one and two residential households

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Sources of Water Rain and Snow replenishes the surface water and underground aquifers Ground Water (aquifers) Surface Water (rivers, lakes, reservoirs)

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Sources of Surface Water California, there are two major arteries serving as the sources of surface water for urban and agricultural areas: The Sacramento-San Joaquin Delta (Bay- Delta) and The Colorado River

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The Delta Delta serves as a major water source for approximately two-thirds of the state – over 22 million people The region is fed by two major rivers: the Sacramento from the north and the San Joaquin from the south

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The Delta Mixture of fresh water from these two waterways and numerous tributaries combine with salty ocean water from San Francisco Bay to create the largest estuary on the West Coast of North America - The San Joaquin Delta. Massive pumps at the southern end of this marsh pull approximately 5.5 million acre-feet annually of fresh water southward to Central Valley farmland via the Central Valley Project and ultimately, to the southern California region via the State Water Project.

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Federal Central Valley Project FDR and U.S. Reclamation Service looking for projects, took over CVP in 1935, began construction in 1937 Eventually completed in 1950s Final cost more than $500 million Distributes more than 3,000,000 acre feet of water Almost all used for agriculture No connections to Southern California initially

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The Colorado River Colorado River winds its way through the southwestern United States before terminating in the Gulf of California in Mexico. Provides water to seven states including California, with each state's water use determined by the Colorado River Compact of 1922. California permitted to use 4.4 million acre-feet annually. For over a decade, California has been using well beyond the 1922 allotment. As water conditions have tightened in several of the other states, the secretary of the Interior has demanded that California reduce its use of the Colorado River - a major challenge to river water users.

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Flood Irrigation continued… Advantages: inexpensive less labor large amounts of water leach salts rodent control

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Flood Irrigation continued… Disadvantages: land must be leveled or contoured uses large amounts of water water loss through evaporation may cause disease in some crops if applied incorrectly run off water can cause problems (silt buildup in rivers, may contain pesticides)

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Furrow Irrigation Used in row crops such as beans, tomatoes, corn, sugar beets other vegetable crops. Similar advantages and disadvantages to flood irrigation.

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Sprinkler Irrigation Many types micro-sprinklers, solid set, aluminum pipe a. Advantages: use less water, more precise amounts of water can be applied, less run off (tail water), may be used on slightly hilly land b. Disadvantages: expensive (installation, labor, filters, maintenance), salt buildup

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Drip Irrigation Used on specific crops, such as grapes, trees (such as almonds, cherries, peaches) a. Advantages: uses less water very precise amounts as well as fertilizer b. Disadvantages: expensive to install, (labor, equipment, maintenance)

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What are concerns people have over the use of irrigation in agriculture? a. Overdraft of underground water supplies (aquifers). b. Water pollution – silt, herbicides, pesticides added to irrigation water runs off into lakes, rivers, etc. c. Concerns over water waste – flood irrigation uses a lot of water d. Production of crops in California that are not water efficient – alfalfa and cotton.

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How has agriculture addressed the publics concerns over water usage? a. The #1 water user in California is ___________________________. (set the record straight) *California and Texas are the only 2 states that do not have regulations on groundwater pumping.

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Erosion Power of a droplet of water striking the soil surface Moves tons of soil Runs off to rivers and streams (siltation) Tons of soil lost

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Pollution What types of water pollution? Underground water supplies… Surface runoff (erosion and contamination from crop and animal activities) Soil water (salts) Pre-ag existance Ag production induced

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Water Pollution Mitigation A couple of Answers Total containment of runoff or drainage from intensive animal facilities…lagoons soil polymers – adhere to water particles preventing their runoff use of IPM and GMOs (reduce the need for chemicals)

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Water Waste Caused by evaporation, infiltration, runoff Flood irrigation is the largest waste of water Drip and micro sprinkler use Cost/economics – as the price of water increases, farmers can afford to use less and must become more efficient.

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Economics Driven Politics For specific types of Agriculture production… Special Treatment, Government Subsidies and Corporate Welfare Water Projects Non-point source pollution in the past Subsidies from government that encourage production of high water use commodities (Cotton and Milk)